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/* $KAME: if_nameindex.c,v 1.8 2000/11/24 08:20:01 itojun Exp $ */
/*-
* Copyright (c) 1997, 2000
* Berkeley Software Design, Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL Berkeley Software Design, Inc. BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* BSDI Id: if_nameindex.c,v 2.3 2000/04/17 22:38:05 dab Exp
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/socket.h>
#include <net/if_dl.h>
#include <net/if.h>
#include <ifaddrs.h>
#include <stdlib.h>
#include <string.h>
/*
* From RFC 2553:
*
* 4.3 Return All Interface Names and Indexes
*
* The if_nameindex structure holds the information about a single
* interface and is defined as a result of including the <net/if.h>
* header.
*
* struct if_nameindex {
* unsigned int if_index;
* char *if_name;
* };
*
* The final function returns an array of if_nameindex structures, one
* structure per interface.
*
* struct if_nameindex *if_nameindex(void);
*
* The end of the array of structures is indicated by a structure with
* an if_index of 0 and an if_name of NULL. The function returns a NULL
* pointer upon an error, and would set errno to the appropriate value.
*
* The memory used for this array of structures along with the interface
* names pointed to by the if_name members is obtained dynamically.
* This memory is freed by the next function.
*
* 4.4. Free Memory
*
* The following function frees the dynamic memory that was allocated by
* if_nameindex().
*
* #include <net/if.h>
*
* void if_freenameindex(struct if_nameindex *ptr);
*
* The argument to this function must be a pointer that was returned by
* if_nameindex().
*/
struct if_nameindex *
if_nameindex(void)
{
struct ifaddrs *ifaddrs, *ifa;
unsigned int ni;
int nbytes;
struct if_nameindex *ifni, *ifni2;
char *cp;
if (getifaddrs(&ifaddrs) < 0)
return(NULL);
/*
* First, find out how many interfaces there are, and how
* much space we need for the string names.
*/
ni = 0;
nbytes = 0;
for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
if (ifa->ifa_addr &&
ifa->ifa_addr->sa_family == AF_LINK) {
nbytes += strlen(ifa->ifa_name) + 1;
ni++;
}
}
/*
* Next, allocate a chunk of memory, use the first part
* for the array of structures, and the last part for
* the strings.
*/
cp = malloc((ni + 1) * sizeof(struct if_nameindex) + nbytes);
ifni = (struct if_nameindex *)cp;
if (ifni == NULL)
goto out;
cp += (ni + 1) * sizeof(struct if_nameindex);
/*
* Now just loop through the list of interfaces again,
* filling in the if_nameindex array and making copies
* of all the strings.
*/
ifni2 = ifni;
for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
if (ifa->ifa_addr &&
ifa->ifa_addr->sa_family == AF_LINK) {
ifni2->if_index =
LLINDEX((struct sockaddr_dl*)ifa->ifa_addr);
ifni2->if_name = cp;
strcpy(cp, ifa->ifa_name);
ifni2++;
cp += strlen(cp) + 1;
}
}
/*
* Finally, don't forget to terminate the array.
*/
ifni2->if_index = 0;
ifni2->if_name = NULL;
out:
freeifaddrs(ifaddrs);
return(ifni);
}
void
if_freenameindex(struct if_nameindex *ptr)
{
free(ptr);
}
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